Linear α-olefin (LAO) refers to C4-C28 and above high-carbon straight chain olefins, as important organic chemical raw materials rapidly grown in nearly 30 years. The uses of alpha-olefins are primarily in the following five categories: 1) Used as co-monomers for making linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), mainly including 1-butene, 1-hexene and 1-octene; 2) used for the production of detergents and detergent alcohols with excellent biodegradability; 3) used for making lubricants, as poly-α-olefins are high-quality synthetic lubricants, mainly including 1-decene and 1-octene oligomers; 4) used for making plasticizer alcohols, which have low volatility and good light stability and oxidation resistance when obtained from C8-C10 linear α-olefins; 5) used for making lubricant additives, drilling fluids, adhesives, sealants and the like. More than 50% of the α-olefins used as a copolymer of polyethylene.
The methods of manufacturing α-olefins include wax cracking, alkane dehydrogenation, ethylene oligomerization and extraction. Currently ethylene oligomerization is the major method for producing α-olefin, which accounts for 94.1% of the total α-olefins produced. The catalysts used in the processes are mainly those of alkyl aluminum, titanium, iron, nickel, chromium, etc. With different catalysts and steps, the technologies of ethylene oligomerization include Ziegler process of CPChem, improved Ziegler process of INEOS, and SHOP process of Shell, Idemitsu process of Idemitsu Petrochemical, and Versipol process of Dupond. The Shell's SHOP process, being complex and long in procedure, contains additional steps such as disproportionation and isomerization in addition to the oligomerization process, and thus is highest in the costs of production, but, on the other hand, has advantages in quality and distribution of products, and is able to convert α-olefins for isomerised olefins. Researches on the catalysts of ethylene oligomerization for making α-olefins showed much progress in recent years, there had been reports and patents on non-homogeneous methods of olefin oligomerization for making α-olefins. With rapid advance of the polyethylene (PE) industry, α-olefins, especially 1-hexene and 1-octene, are now highly in demand. Co-polyethylene of 1-hexene is presently the fastest growing product. There are totally 13 sets of α-olefin production facilities of 11 manufacturers in the world, primarily in North America, Europe, South Africa and Japan. In 2009, the annual α-olefin production capacity in the world is 4,334 kt/a, which became over 4,914 kt/a in 2010.
With the rapid growth of the polyolefin and surfactant industries, there are increasing demands on C6-C8α-olefins as polyolefin comonomers and C10-C18α-olefins as major materials for detergents. Thus, it has significant economic and technological value to enhance the content of such linear α-olefins in the products.